Here's a pair of games played with the same variation in the same tournament on the same day, by two friends who had prepared it together. Here's the story, from Tigran Petrosian, His Life and Games, pp. 45-46:

In those days Tigran was very friendly with Geller. Though the two young men were rivals in tournaments, they often prepared for matches together, and kept no secrets from each other. Petrosian had White against Smyslov in the 13th round, and Geller was also White, against Flohr. The friends decided to try the very same variation out - an extremely sharp and risky one, which involved the sacrifice of a pawn in the Queen's Gambit. The author of this idea was Geller, but he did not have to spend long persuading Tigran. On the seventeenth move - an unusual situation - two identical positions appeared on two different demonstration boards. But then a crisis developed; at the same moment both Geller and Petrosian came to the sorrowful conclusion that their experiment could bring them nothing good. For the sacrificed pawn White did not get any attacking chances, and what was worse, the black pawns on the queen's side were threatening to move forward. 'White hasn't the vestige of an attack' said Flohr, 'Black is attacking'. Geller, the inventive tactician, seeing the threatening phalanx of black pawns lost control and went over into defence. This amounted to moral capitulation, an admission of the incorrectness of his strategy. Neither was it in the spirit of the position, which required courageous, energetic action, if one was to fight to retain the initiative. Tigran thought for a long time over his seventeenth move. The decision he took was risky and paradoxical, but nonetheless in harmony with the logic of the position, since it forced Black onto the defensive. Two years previously, in the seventeenth championship, Smyslov had shattered Petrosian's position by advancing an apparently hopelessly weak pawn. This time Petrosian scored his revenge: his undefended pawn moved forward onto a square attacked by no less than four black pieces. It was a purely positional sacrifice, though if Black had continued correctly, the course of the struggle would not perhaps have been changed. Besides its basic chess value, the move had also psychological strength. Smyslov was so stunned by the move that he immediately committed an error and allowed Petrosian to develop a strong attack. The game was adjourned in a hopeless position for Black... As for Geller, he did not even succeed in adjourning the game. On move 34 the advancing black pawn mass had already forced his resignation.